The reason he didnt raise steve, is because they are both VERY deep (ivey has 1 million infront and durrrr had a lot also , like 700k). So they were maybe 500 BBs deep, maybe more. he wasnt exactly slowplaying, but felt he didnt want to shove for whatever it would be, incase durrrr has a set. If they were only shortstacking each other with poxy 100bbs deep then he would get it in easy.
At no point during the river was he intending to shove on durrrr, it would of been amazing if he did, but he was only beating a worse flush draw, and thats about it, he asks how much durrrr has left and relaises he cant get durrrr to lay down anything other than a stone cold bluff. He knows durrrr is weak now when he bets river because durrrr would check top pair or pair/ combo draws, and durrrr also looked so uncomfortable, so he never has AJ or top 2 in this spot and ivey knows this. and he was considering making "sickest call of all time".
Interesting hand for people like us, but bread and butter for these guys, (hence eli elezra falling asleep)